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Old 02-20-10, 09:32 AM   #1
TromboneAl
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New to Indexed Shifting

After years on bikes with downtube friction shifters, I've gotten a new bike that has STI shifters.

A few questions: What is the purpose of the adjuster on the cable stop for the RD cable?

As with my old bikes, the FD will touch the chain a bit after I shift to some of the larger cogs in the back. I've found that I can move it a bit and resolve this by pushing the small FD shift lever just a little bit. That surprises me, since I had the impression that that lever simply released the "catch" on the cable so that it could drop back by one position, rather than actually moving the derailleur.

Should it be possible to adjust things such that the FD doesn't touch the chain as I shift around in the back?

Thanks,
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Old 02-20-10, 09:51 AM   #2
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Increasing or decreasing cable tension in small increments with the adjuster can make a big difference in fine tuning RD operation.

http://www.parktool.com/repair/readhowto.asp?id=64

I'm used to the adjusting barrels on the SRAM grip- or triggershifters that I use. Not familiar with STI.
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Old 02-20-10, 10:03 AM   #3
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You will be able to trim the front some with lever position. Also, some front shifters have an intermediate position that allows you to "half click" the shift and move the FD a bit. I have really only had this problem on triples, not much trouble with doubles. If you are getting rub as you move around the cassette, consider changing your front ring choice to eliminate the cross chain. I think you will like your new shifters as you use them more. JanMM is spot on about the barrel adjuster.
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Old 02-20-10, 10:10 AM   #4
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Quote:
Originally Posted by TromboneAl View Post
After years on bikes with downtube friction shifters, I've gotten a new bike that has STI shifters.

A few questions: What is the purpose of the adjuster on the cable stop for the RD cable?

As with my old bikes, the FD will touch the chain a bit after I shift to some of the larger cogs in the back. I've found that I can move it a bit and resolve this by pushing the small FD shift lever just a little bit. That surprises me, since I had the impression that that lever simply released the "catch" on the cable so that it could drop back by one position, rather than actually moving the derailleur.

Should it be possible to adjust things such that the FD doesn't touch the chain as I shift around in the back?

Thanks,
Welcome to the 21st century

The STI lever will shift the FD from one chain ring to the other, but it also allows you to shift between two different positions on a chain ring to allow for the change in chain line as you shift across the rear cassette. So for a two chain ring crank you actually have four different FD positions. Once correctly adjusted you can eliminate rubbing between the chain and FD cage by selecting the appropriate FD position depending on where you are on the rear cassette.
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Old 02-20-10, 01:57 PM   #5
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I think you will like your new shifters as you use them more.
Yes. I already like them, although I'm still in the "OK, let's see, the big lever on the right makes it harder, and the big lever on the left makes it easier" stage.
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Old 02-20-10, 05:19 PM   #6
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Yes, if properly adjusted the FD shouldn't touch the chain when you shift RD unless you shift to extreme opposite gears which is not advisable anyway (large-large, small-small). Under normal conditions the FD will "self adjust" when you release the shifter lever and move back a bit. At least that's what happens with MTB FD, I don't exactly remember how road FD acts, I didn't ride a road bike in over two years and it was a triple. So I don't quite understand what Cyclaholic is saying about four different positions.

The tension adjuster, as mentioned above, is for fine-tuning the RD. If you notice that the chain hesitates to shift to a larger cog, it rubs for several rotations before jumping over then the cable tension is too low. If the chain is grabbing the next larger cog trying to shift to it when you don't want it to, the tension is to high.

To lower the cable tension screw the adjuster in, clockwise, to increase the tension unscrew the adjuster counterclockwise. Do this is quarter-turns. So a quarter turn and test by running the chain through all gears, then quarter turn and test again until you get it right.

Check out Bicycle Tutor for instructional videos. He has both for FD and RD adjustments.

If you're going to tune it remember to finish tuning the RD first before you start tuning the FD. And watch the videos, there are few things that are important like starting to tune the RD with cable detached to align it with the smallest cog without any pulling on the RD, tweaking the limit screws, etc. Not terribly difficult things but they need to be done to get the RD and FD working well.

Adam

Last edited by AdamDZ; 02-20-10 at 05:24 PM.
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Old 02-20-10, 05:53 PM   #7
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Originally Posted by TromboneAl View Post
Yes. I already like them, although I'm still in the "OK, let's see, the big lever on the right makes it harder, and the big lever on the left makes it easier" stage.
Same here. I only have indexed shifting on a mountain bike that I seldom ride and I have to think about which lever I need to push.
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Old 02-20-10, 08:40 PM   #8
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Same here. I only have indexed shifting on a mountain bike that I seldom ride and I have to think about which lever I need to push.
Right Rear

with my STI shifters (Sora...) if I push the right lever to the left, the chain moves to the left on the cogs... if i move the left lever to the right, the chain moves to the right on the chainrings...
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Old 02-20-10, 09:55 PM   #9
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Indexed shifting systems are more sensitive to cable tension than friction shifting; the adjuster allows you to fine tune the tension more easily.
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Old 02-21-10, 07:05 AM   #10
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Yes. I already like them, although I'm still in the "OK, let's see, the big lever on the right makes it harder, and the big lever on the left makes it easier" stage.
LOL Reminds me of the first time that I used bar end shifters.

My wife and I bought a new Santana tandem that had bar end shifters (this was pre-indexing). Bar ends are oriented backwards vs. down tube shifters. The first time that we came to a steep hill I wanted to shift into the granny chainring and biggest rear cog at the same time. I think that it took me 5 tries before I could make my brain work both shifters in the desired direction at the same time.
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